While quaternary ammonium compounds are widely used as disinfectants, more potent and/or broader spectrum antimicrobials are desperately needed. For example, small molecule quaternary ammonium compounds are generally ineffective against Gram-negative bacteria, such as E. coli, since these microbes have very sophisticated outer membrane structures that effectively keep out antibacterial agents.
In addition to a cationic site, a significant lipophilic component enhances antimicrobial action. The mechanism of action of these cationic surfactants on bacteria is believed to be one of electrostatic interaction and physical disruption, rather than interference with a metabolic pathway. The cationic site of the agent is able to bind to anionic sites of the cell wall surface. With the lipophilic component present, the agent is then able to disrupt the membrane and permit release of electrolytes and nucleic materials, leading to cell death.